# Define an updated BankAccount class from activity1/task3
# that simulates a bank account with the following new methods:
# (1) deposit_funds - adding money to current balance
# (2) withdraw_funds - withdraw money from current balance. Should check if there is sufficient balance.
# If there is insufficient fund, should not be able to withdraw money. How would you define this method? 
# Should this method return something?
# (3) add_interest - add certain percentage of interest to the current balance









# Once completed, create an instance of BankAccount with your details and 
# make at least one call to each of the new methods, as well as a call
# to retrieve the current_balance at the end.



# In the deposit_funds method, is a negative number allowed? 
# If you did not include validation on the value, please update
# your code to include that. A simple solution is no money is added
# the current balance if a negative amount is deposited into a bank account.




# How about the add_interest method? Can the interest be 0 or a negative number?
# If you have not include validation for that, update your code to deal with it.
